I'd like to get the above to return the singature for the API session when I enter in my public and private key. Is this even possible? Am I barking up the wrong tree? I was hoping I could use InsertFromURL to populate a field with the result, which would be the signature...

Hello, me again! So I've got the webviewer now showing what I want, ie it just displays the 'sig' variable from the javascript originally posted. Now how do I pull that out of the web viewer? I've tried using GetLayoutObjectAttribute, but to no avail...